Let's just rewind here with a few questions.
You say that you tried to change the Pool Address on both of them? Can you confirm that this was so and confirm that they were both at that point accessible?
Then you say that you initiated a software update on the S1, which again implies that you could access it? Which firmware version did you load and what was the last thing you saw on the screen?
On the S3 you say that you tried to change the WAN address which again implies that you had access to the miner at that point? can you confirm this?
Balance of probability is that they are both fine but that you are not now connecting with the correct IP or that it is ouside the range that your PC or Router is set up for?
Best thing is to use the the Advanced IP scanner and see if it can find them?
http://www.advanced-ip-scanner.com/Rich